/**
 * Created by Administrator on 2016/4/2.
 */
import java.util.*;
public class Average3{
    public static void main(String[] args){
        Scanner console=new Scanner(System.in);
        double sum=0;
        int count=0;
        while(true){
            try{

                int number=console.nextInt();
                if(number==0){
                    break;
                }
                sum+=number;
                count++;
            }catch (InputMismatchException ex){
                System.out.printf("略过非整数输入:%s%n",console.next());
            }
        }

        System.out.printf("平均 %.2f%n",sum/count);
    }

}

